Construction material recycling screen SBR4 in operation in Iceland
The production manager, Steingrimur Bragason from Colas Island, discovered the SBR4 at bauma. He quickly realised he would have to submit a proposal for improvement to the management for the recycling process and installation safety. The advantages of simple and robust technology count twice on an island. Fewer moving parts, the absence of hydraulics and conveyor technology as well as electrics reduced to the essentials are made for use far from overnight express deliveries in the middle of the northern Atlantic.
The task, however, is the same as in German asphalt mixing plants. The aim is to reduce crushing and wear costs, to reduce the dependence on the crusher or crushing service provider, and to generally make the preparation and processes more flexible. In operation is the SBR4 with a Volvo 150 with a 3.2 m wide and 4.3 m³ capacity bucket. The screening plant was supplied with a 25 x 25 mm and 45 x 45 mm screen deck for the processing of surface, binder and base course RC.
The tensioning system requires only 8 tensioning screws and there is no need to remove any covers, baffles or the like. This means that changing the 9.6 m² screen surface takes only about an hour with 2 people. The robustness and long service life of the screen linings are also achieved by the bar sizer above the screen deck. Via three different plug-in variants, the bars of the patented system can be positioned without tools to suit the different material flow of the screenings at different inclination settings of the machine. Asphalt clods are separated directly without reaching the screening surface. The milled material, on the other hand, reaches the screening deck without exception and is classified there on the 3 m long screening section. The sizer bars act here as impact protection, promote screening performance and increase the service life of the screens.
The ultrasonic proximity sensor control allows operation at any time without having to leave the wheel loader. In this way, the machine operates with the lowest operating costs and fits optimally into the process, between preparation and mixing plant. The excitation of the vibration system is generated exclusively by two 2 kW electric unbalance motors – on Iceland with electricity from geothermal and hydropower a CO2-neutral operation.
This year, 20 000 to 30 000 t are to be processed with the SBR4 construction material recycling screen. With external crushing costs of 6 to 7 €/t, the screening plant will thus pay for itself in the year of purchase. With the mesh sizes of 25 and 45 mm, 140 t of milled material can be screened per hour without any problems, according to the manufacturer. The undersize material is usually stockpiled and the rock composition, bitumen content and properties are determined by the laboratory. According to these results and the asphalt recipes, new asphalt is mixed from it. The oversize material is stored and later crushed.
In addition to the crushing costs, the avoidance of mixing in larger conglomerates is the main focus of Colas. The 25 x 25 mm mesh separates conglomerates that have formed due to storage from 0 – 11 or 0 – 16 granules. This protective screening prevents the lumps, which do not dissolve in the mixing process, from tearing up the asphalt surface during asphalting. So far, this damage could not be solved by own solutions during addition and led to the removal and re-paving of the asphalt pavement.
Production manager Steingrimur Bragason concludes: “Robust and simple solutions, such as the electrically operated construction material recycling screen SBR4, are made for the conditions here in Iceland.” Florian Schmellenkamp (Head of Business Development EAG, Dresden), who was personally on site for the commissioning, also adds: “If our technology is convincing in tough use in Iceland, then all the more so in our home market in Germany.”
